Different types of comfort layers are already known, such as different layers of polyester fibres that are processed into a comfort layer via carding and that are stuck together by means of melting the fibres.
These known comfort layers feel very nice and are still frequently used to cover pillows, mattresses or other similar objects.
However, a disadvantage of such known comfort layers is that they quickly lose their resilience, as the fibres are repeatedly compressed and when the known comfort layers lack the resilience to reassume their original shape, the product concerned becomes less comfortable and even unfit for use.
Comfort layers that are made of a natural or synthetic latex are also known.
While these known comfort layers do not quickly become compressed and lose their shape, such known comfort layers are disadvantageous in that natural or synthetic latex has a closed cell structure, such that, when such a comfort layer is used on a mattress for example, damp air and sweat cannot be absorbed by the mattress.
A disadvantage linked thereto is that the user will perspire even more, since there is no ventilation, and any feeling of comfort is lost.
The most recent known comfort layer is made of viscoelastic polyurethane foam.
This type of soft foam has properties that are subject to change caused by variations in temperature and behaves like a sort of thermoplastic, such that comfort layers formed of such viscoelastic polyurethane foam become softer as a result of the influence of body temperature and thus “rolls” itself around the body or the head.
A major disadvantage of this material is the large number of closed cells that are present in the foam structure, so that here as well, the necessary ventilation is largely lacking, and the head or body gradually becomes warm or overheated, and perspiration cannot be properly vented.